Changes in the mechanical properties of support materials for segmented-in-series type solid oxide fuel cells as a function of time

As the substrate materials for segmented-in-series type solid oxide fuel cells (SOFCs), the mechanical characteristics, such as Young's modulus, of Al₂O₃-NiO-YSZ, TiO₂-NiO-YSZ and MgO-NiO-YSZ were examined under SOFC operating conditions. The Young's modulus for all of the samples decreased at a high temperature. For the Al₂O ₃-NiO-YSZ samples, the behaviours of the Young's modulus changed at each process including as-sintered, 100 h reduction and 2000 h reduction. For the TiO₂-NiO-YSZ samples, the Young's modulus behaviour varied between the as-sintered and reduced samples. However, further reduction did not change the behaviour of the Young's modulus. For the MgO-NiO-YSZ samples, the Young's modulus of the samples exhibited a nearly constant behaviour through the sequence of processes from as-sintered to 100 h reduction and 2000 h reduction. Based on the microstructural analysis, the compositions of the framework of the samples and the sliding of the grain boundary strongly affected the Young's modulus.